Over on Free Range Kids, there's a post about kids, PE, nutrition, and health (inspired by this). I was going to leave a comment but I think I need a little more room to organize my thoughts.
Oddly, more PE, healthier lunches, and nutrition education doesn't make kids skinnier. Who would have guessed? It might have made the kids healthier but apparently they didn't check for that. I don't think this study means we should scrap PE (or daily PE) or not worry about what the schools feed them.
I don't think PE teaches kids to be healthier. It can give kids the tools to be healthier, if it's done right. It's possible to introduce kids to different sports and activities that they may enjoy for life. It may not but it might. Giving kids the basics of basketball will allow them, if they want, to join pick up games later in life. (BTW, you have to teach some of those basics. My little sister was marked down in PE in Kindergarten because she didn't know how to dribble a basketball. At my parents house didn't have a basketball hoop, a basketball, or anyone to have ever shown her how to dribble. Where was she suppose to have learned it?) Recess, I think, has an even better chance to help kids be healthier now and throughout life because it lets them choose the activity. We had tons more fun playing soccer or rugby (only for a few days then a teacher made us stop tackling) at recess (which we had every non-rainy/snowy day K-6*) than I ever had playing soccer or flag-football in various grades' PE classes. Recess tends to get dumped before PE in elementary schools because the classroom teachers get a break from the kids - often the only one they get all day. But recess is more important for the kids; they burn off energy, get to take a mental break, learn to negotiate rules, etc with one another, and a bunch of other important stuff. (I don't feel like looking all the benefits of recess up in my old pedagogy texts.) Anyway more PE may not help but maybe better PE could. Not everyone is athletic but helping kids have fun being active might help them be more active as an adult.
Healthier lunches and nutrition education, again, may not help in the short term but it might help long term. First of all "forcing" kids to make relatively healthy decisions at school will reinforce what they (hopefully) are learning at home. However, we have to keep in mind that kids are programed to prefer fat, salt, and sweets more than adults are. (There was a segment on NOVASscienceNOW on this recently.) Their tastebuds are different and you have to keep offering new foods before they'll really try it (ask any parent). We certainly shouldn't be encouraging junk food.
But in the end what kids learn in school can be unlearned at home. If a child isn't being encouraged to play outside, doesn't see his/her parents be active, is given unhealthy food to eat and has unhealthy eating modeled for him/her, I'm not sure what the school teaches will make the difference in the long run. And focusing on weight instead of health isn't helpful for anyone**.
*and if we were stuck inside several days in a row they'd figure out times a couple of classes could use the gym for recess
**If I found out a particular person was the reason my ELEVEN YEAR OLD sister (not one of the tallest or skinniest kids in her class but in no way overweight) was asking me this weekend if I thought she needed to lose weight, I will kick his/her ass up one side of town and down the other. ("I weighs 80 pounds now and I used to be 70lbs." [read in worried tween voice] I pointed out she used to be shorter, too; I'm not sure she's convinced.)